[Nognar]

Thank you for that.

Spent a few hours today having a looking and running the measuring blocks on VAGCOM.

Managed to take the G150 sensor out, but my word is it difficult to get to. I suspect I just have big hands or should have taken more trim out apart from the transmission tunnel cover. Getting to it, turning it, pulling it out and getting the thing out was very frustrating!

Anyway, had another old sensor available and confirmed with VAGCOM that disconnected I got 0c and the sensor plugged in I got a reading.

The new sensor gave a little lower temp reading than the prior one but there really was not much in it.

But as VAGCOM was running I could see the temps on G150/ 151 were say 22c so if I upped the level on the HVAC beyond the reading on the colder sensor there was heat.

Interestingly enough if I turned the HVAC off for a couple of minutes with the car running then turned it on again I got a huge initial blast of heat from it so there is heat in the system ok.

So I suspect I have two problems here, the readings from G150/151 are a little high so I have ordered new parts. Also the two sensors are reading different temps, I firstly thought this was just a bad sensor but the more I think about it the two heater matrixes are not performing to the same level.

As in one is much hotter than the other which is throwing the system out and confusing and already overly complicated HVAC system.

Therefore two new sensors and another flush of the cooler matrix I hope will solve the problem.

Its one way to spend time on a Sunday!